Yarns are commonly processed in warp sheet form, such as by drawing and heating the warp sheet while it longitudinally advances. Processes of this type are disclosed in U.S. Pat. No. 4,407,767 to Seaborn, and U.S. Pat No. 4,630,340 to Bauer et al, and German OS No. 3323202.
In a typical process of the above type, the warp sheet contains many yarns, for example more than 100 yarns, and the yarns have a small lateral spacing or gauge. Also, the warp sheet advances onto the draw rolls of a godet having a length for example of about one meter, and the yarns are drawn or subsequently heat treated under a relatively low yarn tension. In this process, it is necessary to guide the yarns of the warp sheet by means of a reed. Such reeds conventionally comprise a plurality of pins aligned in a direction which is transverse to the longitudinal advance of the yarns, and with the pins being separated a uniform distance or gauge and such that adjacent pins define a yarn receiving slot therebetween. The thread-up of such yarn reeds is a time consuming and labor intensive operation and it is accordingly an object of the present invention to provide an apparatus and method for threading the warp sheet onto a reed of the described type, and onto the draw rolls.